AU2005287456B9 - System and method of adapting sub-picture data for being displayed on mini-screens - Google Patents

Abstract

A computer system (40) and method for adapting subpicture data for being displayed on a user device (10) having a small screen (12), the subpicture data being temporally correlated with associated video data, the method comprising the steps of: reading (S1) subpicture data from a source; determining (S2) a subpicture data portion from the read subpicture data which has a readability value less/greater than a predetermined readability limit; and partitioning (S3) the subpicture data portion into at least two subpicture data portion parts, and re-sizing (S4) the subpicture data portion parts such that each of the subpicture data portion parts has a readability value which is equal or greater/equal or less than the predetermined readability limit.

Description

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00 p System and method of adapting sub-picture data For being displayed on min-screens Field of the Invention The present invention relates to a system and method for adapting subpicture data for being displayed on an display IsO with a smaller resolution a display of a PDA), the subpicture data being temporally correlated with 00 associated video data.

(N SBackground Ce- Recently, the use of Personal Digital Assistants (PDAs) became more and more popular. PDAs include small format organizers and often do not have any keypad. Control of a PDA can be accomplished by touching its screen using, for example, a pen.

A lot of different operating systems (OS) are used for PDAs, but the two main platforms are Palm OS from Palm Inc. and Pocket PC from Microsoft, who both license their system to third party manufacturers. Another PDA operating system which is popular in Europe for wireless devices is Symbian. Pocket PC 2003 is the most up-to-date OS.

Features include: Pocket Internet Explorer, a new Windows Media Player, Network Access, MSN messenger, Infrared Communication, Connection Manager, Enhanced Pocket Outlook, Updated Pocket Word and Excel, and is similar in appearance to a Windows XP desktop.

Common PDAs unite a plurality of functions such as the functionality of pocket calculators, electronic telephones and address registers, notebooks, PCs and mobile phones.

Normally, DVD-video data also includes subtitles, e.g.

information representing text which is spoken e.g. by actors (which is particularly helpful for hard of hearing persons or persons not understanding the language spoken).

N\Melbourne\Cases\PaIet\7 1000-71999\P71 709AU\Specis\P71 709AU SpEcifcaioi 2008-7-30.doc 01/08/2008 00 However, since the geometrical size and resolution of the Sscreens is smaller than the one that the subtitle has been originally been made for, subtitle text displayed thereon is difficult to read if resized with the same ratio as the underlying video. If the resize of the subpicture is done I\ less than the video, the subpicture data might be out of the screen on the left and right side, or becomes 00 predominant in the screen so that it is overlaying a big 0 C 10 part of the video.

C-i Summary of the Invention According to a first aspect, the invention provides a method for adapting subpicture data for being displayed on a user device having a display screen a resolution of which is smaller than the resolution for which the subpicture data has been optimized for, the subpicture data being temporally correlated with associated video data, comprising the steps of: reading subpicture data from a source; determining a subpicture data portion from the read subpicture data which has a readability value less/greater than a predetermined readability limit; and partitioning the subpicture data portion into at least two subpicture data portion parts, and re-sizing the subpicture data portion parts such that each of the subpicture data portion parts has a readability value which is greater than/equal to or less than the predetermined readability limit, wherein the step of determining a subpicture data portion includes the step of calculating a data portion display period for the subpicture data portion and of calculating N :Mebourne\Cases\Patent\71 000-71999\P71 709.AU\Specis\P7 1709AU Speificabo, 2008.7-30.doc 01/0812008 4 00 0 part display periods for the at least two subpicture data portion parts using the portion display period for a subsequent display of the at least two subpicture data portion parts.

According to a second aspect, the invention provides a \O data processing system, comprising: In 00 means for reading subpicture data from a source; C( Smeans for determining a subpicture data portion from the read subpicture data which has a readability value less/greater than a predetermined readability limit; and means for partitioning the subpicture data portion into at least two subpicture data portion parts, and for re-sizing the subpicture data portion parts such that each of the subpicture data portion parts has a readability value which is greater than/equal to or less than the predetermined readability limit, wherein the means for determining a subpicture data portion is adapted for calculating a data portion display period for the subpicture data portion and of calculating part display periods for the at least two subpicture data portion parts using the portion display period for a subsequent display of the at least two subpicture data portion parts.

N \Melbourne\Cases\Patent\7 1000-71999\P71 7O9AU\Specis\P71 709.AU Speaifcation 2008-7-30.doc 01/0812008 00

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0 It is to be understood that the features mentioned above and those still to be explained below can be not only in Sthe combination respectively mentioned, but also in other combinations or in isolation without leaving the scope of the present invention.

INC Brief Description of the Drawings Examples of the invention are shown in the drawings and 0 will be further explained in the following in more detail.

Cl 10 In the drawings: C- Fig. 1 is a schematic perspective view of a conventional PDA; Fig. 2 shows a quantity of subtitle data and its subsets; Fig. 3 is a flow chart of a first embodiment of the method according to the present invention; Fig. 4 is a flow chart illustrating a second embodiment of the method of the present invention; and Fig. 5 is a system according to an embodiment of the present invention.

Detailed Description In the following, the term "subpicture data" is used as a generic term which includes information such as subtitle, hot spot tinting, overlay graphics, etc.

On a DVD-video disc, for example, subpicture text is stored separately from a main video, usually in the form of low bit-depth (4 color) images. Separately means that the subpicture data exists apart from the main video information, specifically N:\MeboumeXCases\Patent\ 1000-71 9991P7 1709.AUkSpecis\P71 709.AU Specificalioti 2008-7-30.doc 0110812008 WO 2006/032516 PCT/EP2005/010305 9 so that the subtitle can be displayed, or not, at a viewer's discretion.

While the DVD specification (generally MPEG-2) supports up to 32 separate subpicture data streams, any one stream is limited to just 3.36 Mbps bandwidth. To meet the bandwidth requirement as well as to simplify the process of combining them with the main video, subpictures are often composed as run-length encoded bitmaps. Each pixel in such a subpicture image is assigned as a value from a fixed palette of 16 colors.

Each subpicture pixel can be specified as one of four pixel types: background, foreground, emphasis-1 and emphasis-2. Each pixel type can have a different color and transparency value.

Additionally, each subpicture pixel's color and transparency can be changed from field to field or from frame to frame. The palette as such can be changed on every program chain (PGC) transition.

Consequently, subpicture data is defined in a very efficient and flexible way that enables, extensive multi-language or other forms of program augmentation while the data stream is kept down to a manageable bitrate.

There are several ways for final display of the subpicture data on a screen, one of which is hardware mixing.

Hardware mixing involves simply taking, the subpicture text and placing it on top of the video data. Wherever a subpicture pixel overlaps or overlays a video pixel, it replaces it, completely over-writing the video pixel underneath.

00 Another way is hardware alpha-blending. Hardware alpha blending involves blending the subpicture image data with Sthe underlying video data using varying levels of transparency, as dictated by an alpha-channel. This alpha channel contains a mask that determines how much of the subpicture data is blended with the background video data, and at what percentage.

In 00 Fig. 1 shows an exemplary conventional PDA or pocket PC C1 10 c- The PDA 10 includes a display or screen 12 such as an LCD, a housing 14, a menu selector 16 and a memory slot 18. The memory slot 18 can receive a portable memory unit: which is not shown in Fig. 1. Video data can be stored in the memory unit.

The PDA 10 can also include an internal memory for storing data, particularly entertainment data such as audio files (MP3, wave files, etc.), video files (MPEG-2, MPEG-4, etc.) and the like.

In Fig. 1, the screen 12 of the PDA 10 displays a movie scene including a two-line subtitle text 20. However, embodiments of the present invention is not only applicable to small screens of PDAs. An embodiment of the invention is also applicable to devices smart phones) having small sized screens and to any devices with a smaller resolution as the resolution for which the subpicture data has been optimized for.

An entire quantity 1 of subpicture or subtitle data is depicted in Fig. 2.

The quantity 1 includes subpicture data which is to be adapted to be display with a high resolution on a small sized screen, and other subpicture data which does not N:\Melbourne\Cases\Patent\71000-71999\P71709 AUSpecisP71709.AU Speoficaion 2008-7-30.doc 01108/2008 00 O need to be adapted since its resolution on a small sized screen is already satisfactory. The subpicture data to be Sadapted is indicated with reference numeral 2 and depicted as a subset of the entire subpicture data quantity 1.

The subpicture data to be adapted will be determined in I\ one of the steps of the method according to an embodiment of the present invention, as will be explained below. This 00 subpicture data to be adapted will hereinafter also be Cl 10 called "subpicture data portion". The seam around the Ssubpicture data portion 2 represents data which is not to C-q be adapted necessarily since its resolution is good enough to allow a satisfactory readability thereof on a small sized screen. Preferably the playback device "knows" that is no optimization needs to be done.

On the other hand, the subpicture data portion 2, wherein there may also be a plurality (not shown) of subpicture data portions 2, can further be (sub-)divided into a plurality of subpicture data portion fragments or parts 3.

In the following, the relations explained above with respect to Fig. 2 are further explained on the basis of some exemplary subtitles, as they occur e.g. in movies, the movies can be stored on a DVD.

#1 "Hey, Bart! You are not supposed" "to torment Lisa!" "I didn't!! She's annoying ME!!" #2 "Hasta la vista, baby!" #3 "We are very happy to have you here in our fantastic show" The first example consists of three textual lines which contain information being actually spoken by movie N:\Melbourne\Cases\Paten\71000-71999\P71709AU\Specis\P71709AU Speificaiori 2008-7-30doc 01/08/2008 00 0 characters, here by characters of the animated cartoon series "The Simsons", i.e. the text can be heard by a Sviewer, and simultaneously are displayed visibly on a screen. This first example is a potential subpicture data portion candidate for being adapted according to the method according to an embodiment of the present \D invention, as will be explained in more detail below, in order to be displayable with a satisfactory resolution on OO a small sized screen.

00 N 0 The first example represents in the light of Fig. 2 a Ci subpicture data portion 2, which may have a display period of 12 s, for example. This portion 2 can be divided into three subpicture data portion parts 3, the first being represented by the first line, i.e. by "Hey, Bart! You are not supposed", the second part by the second line "to torment Lisa!", and the third part by "I didn't!! She's annoying ME!!" As will also be explained in more detail below, these three subpicture data portion parts 3 may be assigned either equal (4s each) or different display periods (e.g.

2s 5s) depending on a respective length of each of the parts 3.

The second example may represent a textual single-lined subtitle which does not need to be adapted since it may be regarded as having a sufficient readability.

NAMelbourne\Cases Paleri\71000-71999\P71709AU\Specis\P71709AU Specification 2008-7.30.doc 01/08/2008 WO 2006/032516 PCT/EP2005/010305 13 The third example is also a single-lined subtitle. However, it is much longer in comparison to the second example. Displaying the third exemplary subtitle on a small sized screen may be difficult for a viewer to read. Therefore, even a single-line subtitle can be divided into parts 3. In the case of example 3, a first part 3 could be represented by "We are very happy to have you" wherein the rest "here in our fantastic show!") is represented by a second part 3, both parts 3 being adapted to be displayed as single-line subtitles each having either half of the display period of the original subpicture data portion of "We are very happy to have you here in our fantastic show") or any other arbitrary (possible) display period division.

Preferably the resolution change for the subtitles doesn't change throughout the playback, or it changes always for adapting to the space available.

Fig. 3 shows a first embodiment of the method of the present invention.

In a first step S1 subpicture data are read or received from a source, e.g. from a DVD-movie disc, for providing base subpicture data which is to be adapted, if necessary.

In step S2 it is determined from the data read in step S1 if a subpicture data portion is present. As mentioned above, a subpicture data portion is an amount of data which belongs to the read subpicture data, wherein a readability thereof is poor.

Subpicture data having a poor readability is selected from the read subpicture data and hereinafter referred to as subpicture WO 2006/032516 PCTiEP2005/010305 14 data portion. However, generally not all of the read subpicture data are classified as poor.

Hence, a readability value is determined for each of the read subpicture data. The readability value can be defined in many different ways depending on the type of the subpicture data such as the file format in which the data are stored.

If the subpicture data are stored, for example, as bitmaps, the readability value could be determined by detecting the actual visual overlap percentage of the subpicture data when being mapped on associated video data. For example, if a subtitle is initially displayed with a very small font size, the actual visual overlap percentage, and therefore the resolution, is rather low. This might also happen when, for example, only a single line of subtitle is displayed by a corresponding bitmap.

In such a case, a probability that a predetermined readability limit, which can be a predetermined resolution, is remained under is rather high. In this manner, the subpicture data portion can be detected when the readability value is less than the readability limit.

Alternatively, the readability value can be based on a number of subtitle lines to be displayed (cf. example. #1 above). If the number of subtitle lines is high, i.e. more than one, it is likely that the respective lines become harder to read, particularly when displayed on a very small screen such as an LCD of a pocket PC. In this case, the readability limit can be defined as a maximum number of subtitle lines which are (still) allowed to be displayed without the need to change the presentation thereof. However, in general, already two subtitle lines WO 2006/032516 PCT/EP2005/010305 being displayed simultaneously are hardly recognizable on a mini-screen.

In step S3 the subpicture data portion is partitioned into at least two subpicture data portion parts. Then these subpicture data portion parts are re-sized. By the step of partitioning the subpicture data portion the amount of subpicture data, which has to be displayed at once, is reduced. This allows to re-size the respective parts to a (geometrical) size (i.e.

resolution) which is well recognizable for a viewer.

Of course, this might also cause an adaptation of a display timing. Adaptation of display timing will be explained below.

Alternatively, the so-generated subpicture data portion parts may be stored for repeated playback operations (not shown in Fig. 3).

In Fig. 4 a second embodiment of the method of the present invention is schematically shown.

In a first step S31 subpicture data which are included in video data such as, for example, MPEG-2 data and which are temporally correlated therewith are read into a memory of a data processing unit such as, for example, a PC.

If the data are provided on a DVD-video disc, the data are normally stored in the MPEG-2 file format. A playback device such as, for example, the PDA 10 of Fig. 1 recognizes DVD-video data by a directory entitled "VIDEO_TS". This directory contains, in the MPEG-2 standard, all files relevant for display.

WO 2006/032516 PCT/EP2005/010305 16 The directory VIDEO TS contains files having one of the following three endings '.BUP, and The '.IFO' ending represents index files. The 'BUP' endings represent corresponding backup files. The actual audio and/or video data is contained in files having the endings '.VOB' (Video Object).

VOB files contain audio data, video data and/or subtitle data which are multiplexed. In order to play back, the playback device first has to de-multiplex the data. A VOB file, in turn, also includes a navigation pack (NV_PCK) which contains jump instructions and timing information, and one or more Group of Pictures (GOP) which, in turn, comprise video packs (VPCK), audio packs (A_PCK) and subtitle packs (SP_PCK), i.e. the actual video/audio and/or subtitle data.

All this information is read in step S31 for allowing especially the subpicture data, e.g. the subtitle data, to be analyzed. Subtitle data are often stored in the bitmap format During playback the subtitle bitmaps are overlaid with the actual video data. However, even if the subtitle data are not stored in the bitmap format 'bmp', the method of the present invention can still be carried out. Another subtitle format merely influences the way in which the subtitle data are to be analyzed.

In the second step S32, it is determined which of the subpicture data represents a multi-line subpicture data, e.g. by pattern recognition. Multi-line subpicture data represents, for example, subtitle which is to be displayed in two or more lines. As shown exemplarily in Fig. 1, the subtitle 20 is displayed in two lines. However, since the display 12 of the PDA WO 2006/032516 PCT/EP2005/010305 17 is very small, e.g. only 4 inches in diagonal, character size becomes really small. The subtitle text 20 is hardly readable.

Thus, in step S32 subtitle data which are displayed in two or more lines are identified for further processing.

In a third step S33 time stamps of correspondihg video data, i.e. start time and end time, can be determined. The video data are associated with the multi-line subpicture data which have been determined in the step S32.

Alternatively, only the number of (subtitle) lines of the multi-line subpicture data also can be determined. The number of lines can be used for calculating the display time for each of the single-lined subtitles to be generated.

Of course, both the number of lines and the time stamps can be determined in step S33 in common.

In a further step S34, it can be determined whether or not temporal breaks or interruptions are present. This means, it is determined whether or not further subtitle is to be displayed either temporally before and/or after the actual subtitle data which is determined in step S32. Sometimes several multi-lined subtitles are to be displayed one after the other. In this case, there is no temporal break in the subtitle's temporal stream. Hence, the available time for displaying the respective subtitle is fixed.

WO 2006/032516 PCTiEP2005/010305 18 If it is determined that no temporal break is present, i.e.

there are further subpicture data portion temporally preceding and/or succeeding, the display time of this actual subpicture data portion can readily be divided by the number of charcter lines which is also determined in step S3 for getting the time available for the respective subtitles.

For instance, if the number of a subtitle lines which are to be displayed at once is 3 and the display time for this threelined subtitle data is 18 seconds, the display time being available for each of the single lines is 6 seconds.

It is also possible to divide the available time in a different manner, e.g. 3s 4s lls or 3s+lsP+4s+lsP+9s (IsP means 1 second pause in between, but could be of course also 5 s pause as example). This decision could be made dependent on the respective length, i.e. the semantic content, of each subtitle line.

On the other hand, if it is determined in step S34 that there are temporal breaks, i.e. either temporally before and/or after the multi-line subpicture data determined in the step S32, an optimized display time can be calculated in a step S36.

Optimized display time means that it can be, extended.

For example, after a three-lined subtitle phase in a movie there is a subtitle pause in which no information has to be displayed. Depending on the length of this pause the length of display time of one or all the single-lined subtitles, which are to be generated instead of the initial multi-lined subtitle, can be varied.

WO 2006/032516 PCT/EP2005/010305 19 Again, depending on the semantic content of each single-lined subtitle the display time can be adapted correspondingly.

In a step S37, a plurality of single-line subpicture data is generated using the information obtained in the preceding steps. The geometrical display size, e.g. the character size, of the respective single-line subpicture data can be adapted to the size of a corresponding (original) single-lined subtitle.

If desired, the size can also be increased since merely singleline subpicture data are to be displayed after the method of the present invention has been employed to data containing multi-line subpicture data. Even the size of originally singleline subpicture data can be increased in order to improve the readability of the subtitle.

After the single-line subpicture data is generated, this data can be stored either in the source from which the original data were read or in another memory.

Fig. 5 is a block diagram showing a system 40 according to the present invention.

The system 40 of Fig. 5 can be implemented, by a PC or the like. It includes a memory 42 into which the subpicture data can be read, for example, from a DVD 43 or any other proper storage medium. The system further includes means 44 for reading the subpicture data, means for determining 46 a subpicture portion, and means 48 for partitioning and re-sizing. The means 44, 46, and 48 can be implemented, for example, by a mircroprocessor or a CPU WO 2006/032516 PCT/EP2005/010305 It is to be understood that subpicture data may not only display text lines, but also character lines representing menus, navigation icons and the like.

The method of the present invention can be implemented as software and/or as hardware. Therefore, a computer system or a data processing system can be provided, being adapted to carry out the method of the present invention. The invention may also be implemented as a software tool or even in a DVD playback device. A computer readable medium may be one of a CD-ROM, DVD, floppy disc, hard disc, etc.

The examples given above for defining the readability value are only of exemplary nature and not intended to limit the definition. The readability value can also be defined by the area (in the sense of a bar) a subtitle line takes, when displayed, independent of the actual overlap of the subtitle pixels over the video pixels.

Further, it is apparent that all subpicture data can be adapted in order to obtain a standardized resolution of the subpicture data on small sized screens.

Alternatively, the subpicture data portion parts 3 could also be combined again such that they form a continuous text which runs through the screen, preferably as a horizontal band.

While the invention has been particularly shown with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that various other changes in the form 21 00 and details may be made therein without departing from the scope of the invention as defined by the appended claims.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary IN implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, Si.e. to specify the presence of the stated features but r 10 not to preclude the presence or addition of further Sfeatures in various embodiments of the invention.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

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Claims (24)

1. A method for adapting subpicture data for being displayed on a user device having a display screen a resolution of which is smaller than the resolution for I\ which the subpicture data has been optimized for, the subpicture data being temporally correlated with associated video data, comprising the steps of: 09 (N Sreading subpicture data from a source; determining a subpicture data portion from the read subpicture data which has a readability value less/greater 1i than a predetermined readability limit; and partitioning the subpicture data portion into at least two subpicture data portion parts, and re-sizing the subpicture data portion parts such that each of the subpicture data portion parts has a readability value which is greater than/equal to or less than the predetermined readability limit, wherein the step of determining a subpicture data portion includes the step of calculating a data portion display period for the subpicture data portion and of calculating part display periods for the at least two subpicture data portion parts using the portion display period for a subsequent display of the at least two subpicture data portion parts.

2. The method of claim 1, wherein the readability value is obtained by the ratio of an area the original subpicture data actually overlaps when being displayed and a total area the video data takes, when being displayed.

N:AMelbourne\Cases\PatenI\71000-71999\P71709.AU\Specis\P7 I709.AU Spedfictiion 2008-7-30doc 31107/08 -23- 00 S3. The method of claim 1, wherein the readability value is obtained by determining a number of character lines, the Srespective character lines being displayed when the subpicture data is displayed.

4. The method of claim 3, wherein the step of determining DO the subpicture data portion includes the step of determining subpicture data which is to be displayed in a number of OO character lines which is at least two; and determining the number of character lines. C(

5. The method of claim 4, wherein for each character line of the subpicture data portion respectively one subpicture data portion part having a predetermined display size is generated.

6. The method of claim 1, further comprising the step of storing the at least two subpicture data portion parts in the source or in another memory.

7. The method of claim 6, wherein the display period includes a start time and an end time which are temporally correlated with the associated video data, respectively.

8. The method of claim 7, wherein the start and the end times are assigned to the subpicture data portion parts such that the temporal correlation between the subpicture data portion and the video data associated thereto is maintained.

9. The method of claim 6, further including the step of determining whether or not a further subpicture data portion is present, the further subpicture data portion temporally preceding or succeeding the subpicture data portion.

The method of claim 9, wherein start and end times of each of the subpicture data portion parts are optimized, if N:lMerboumeXCases\PatenX7 100071999\P71 709.AU Specis\P7 1 709AU ;peificaion 2008-7-30.doc 31/07/08 -24- Sno further subpicture data portion is present. (N

11. The method of claim 10, wherein a total display period of the subpicture data portion parts is greater than a display period of the corresponding subpicture data portion. S12. The method of one of the preceding claims, wherein r- the source is a movie data file, particularly a DVD-video C( 10 data file.

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13. The method of claim 12, wherein the file is stored in a memory of the user device.

14. The method of one of the preceding claims, wherein the stored subpicture data portion parts replace the corresponding subpicture data portion.

The method of claim 4, wherein the step of determining the number of character lines includes applying pattern recognition.

16. The method of one of the preceding claims, wherein the subpicture data is subtitle data.

17. The method of one of the preceding claims, wherein the step of re-sizing is performed such that a desired resolution for the subpicture data is the same for all the subpicture data after carrying out the method steps above.

18. The method of one of claims 1 to 16, wherein the step of re-sizing is performed such that different desired resolutions are obtained for the subpicture data after carrying out the method steps above. N:\Meboume\Cases\Patent7 1000-71999\P7 1 709.AU\Specis\P71 709AU Specficaion 2008-7-30.doc 31t0708 00 0 0

19. The method of one of the preceding claims, wherein the subpicture portion parts are combined such that they Sform a continuous band which is displayable running through the screen.

A data processing system, comprising: \O means for reading subpicture data from a source; 00 CI 10 means for determining a subpicture data portion from the read subpicture data which has a readability value C( less/greater than a predetermined readability limit; and means for partitioning the subpicture data portion into at least two subpicture data portion parts, and for re-sizing the subpicture data portion parts such that each of the subpicture data portion parts has a readability value which is greater than/equal to or less than the predetermined readability limit, wherein the means for determining a subpicture data portion is adapted for calculating a data portion display period for the subpicture data portion and of calculating part display periods for the at least two subpicture data portion parts using the portion display period for a subsequent display of the at least two subpicture data portion parts.

21. A computer program comprising computer program code which, when executed in a data processing system, enables the data processing system to carry out the method of one of claims 1 to 19.

22. A computer program of claim 21, which is stored on a computer-readable medium. N:\Melboume\Cases\Palen\71000-71999\P71709.AU\Specis\P71709.AU Specificalion 2008-7-30.doc 31/07/08 -26- 00

23. A computer program of claim 21, implemented as a Ssignal for transmission over the Internet.

24. A computer program of claim 21, implemented as a software tool. \O A computer program of claim 21, being implemented as 00 a computer program product. rsl N:\Melbourne\Cases\Patent\71000-71999\P71709.AU\Specis\P71709AU Specifica:ion 2008-7-30.doc 31/07/08